AF

Chapter 18: Metals

Metals

  • Metals are found in group 1, group II and the Transition Block of the periodic table.
  • As we go down the group there is an increase in metallic character.

Properties of Metals

Reactivity with water

  • Metals react with cold water and form a metal hydroxide and hydrogen gas

  • [ ] metal + water → metal hydroxide + hydrogen

  • [ ] For example calcium: Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g)

Reactivity with acids

  • metal + acid → salt + hydrogen

  • [ ] Fe (s) + 2HCl (aq) → FeCl2 (aq) + H2 (g)

Reactivity with oxygen

  • metal + oxygen → metal oxide
    • [ ] 2Cu (s) + O2 (g) → 2CuO (s)

Reactivity series

Reactions with Aqueous Ions & Oxides

  • Example> COPPER (II) OXIDE

  • [ ] Magnesium is above copper in the reactivity series,

  • [ ] magnesium is more reactive so can displace copper from its oxide

  • [ ] Copper is reduced

  • [ ] The reducing agent in the reaction is magnesium: copper oxide + magnesium → copper + magnesium oxide

  • [ ] CuO (s) + Mg (s) → Cu (s) + MgO (s)

Displacement reactions

  • Displacement reactions between metals and aqueous solutions of metal salts

  • [ ] Any metal will displace another metal that is below it in the reactivity series from a solution of one of its salts

  • [ ] Magnesium + copper sulfate

  • [ ] Magnesium is a reactive metal and can displace copper from a copper sulfate solution

, more reactive metal slowly disappears from the solution, displacing the less reactive metal.

Decomposition reactions

  • Thermal decomposition reactions: Some compounds decompose or breakdown when they are heated to sufficiently high temperatures

  • These reactions are called thermal decomposition reactions.

  • metal hydroxide → metal oxide + water

  • [ ] Zn(OH)2 (s) → ZnO (s) + H2O (l)

  • metal carbonate → metal oxide + carbon dioxide

  • [ ] MgCO3 (s) → MgO (s) + CO2 (g)

  • metal nitrate → metal nitrite + oxygen

  • [ ] 2NaNO3 (s) → 2NaNO2 (s) + O2 (g)

  • metal nitrate → metal oxide + nitrogen dioxide + oxygen

  • [ ] 2Cu(NO3)2 (s) → 2CuO (s) + 4NO2 (g) + O2 (g)